Share-based compensation (Tables)

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Abstract]

Schedule of Share-Based Compensation by Line Item in Consolidated Statements of Income

The following tables present the detail of share-based compensation expense by line item in the consolidated statements of income as well as by award type, for the years ended December 31, 2022, 2021, and 2020:

	Year Ended December 31,
(U.S. Dollars, in thousands)	2022		2021		2020
Cost of sales	$	826	$	779	$	705
Sales and marketing		3,865		3,385		3,620
General and administrative		12,917		10,289		10,624
Research and development		835		979		1,258
Total	$	18,443	$	15,432	$	16,207

	Year Ended December 31,
(U.S. Dollars, in thousands)	2022		2021		2020
Stock options	$	1,114	$	1,893	$	2,571
Time-based restricted stock awards and stock units		9,452		7,437		8,485
Performance-based / Market-based restricted stock units		6,425		4,414		3,509
Stock purchase plan		1,452		1,688		1,642
Total	$	18,443	$	15,432	$	16,207

Schedule of Assumptions Used in Determining Fair Value of Stock Options

The fair value of time-based stock options is determined using the Black-Scholes valuation model, with such value recognized as expense over the service period, which is typically four years, net of actual forfeitures. A summary of the Company’s assumptions used in determining the fair value of the stock options granted during each of the years ended December 31, 2022, 2021, and 2020, is shown in the following table. The Company did not grant any time-based stock options in 2022.

	Year Ended December 31,
	2022		2021		2020
Assumptions:
Expected term (in years)		—	6.0		5.5
Expected volatility		—	34.4% – 34.8%		30.2% – 35.1%
Risk free interest rate		—	0.83% – 1.25%		0.28% – 1.65%
Dividend yield		—		—		—
Weighted average grant date fair value		—	$	12.33	$	8.74

Schedule of Stock Option Plans

Summaries of the status of the Company’s stock option plans as of December 31, 2022, and 2021, and changes during the year ended December 31, 2022, are presented below:

	Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
Outstanding at December 31, 2021		1,397,054		$	39.20
Granted		—		$	-
Exercised		(575	)	$	21.78
Forfeited or expired		(97,088	)	$	38.14
Outstanding at December 31, 2022		1,299,391		$	39.29		3.77
Vested and expected to vest at December 31, 2022		1,299,391		$	39.29		3.77
Exercisable at December 31, 2022		1,040,523		$	40.70		3.13

Schedule of Changes in Time-Based and Market-Based Restricted Stock Awards and Stock Units

A summary of the status of our time-based and performance-based and/or market-based restricted stock units as of December 31, 2022, and 2021, and changes during the year ended December 31, 2022, are presented below:

	Time-based Restricted Stock Awards and Stock Units					Performance-based and/or Market-based Restricted Stock Units
	Shares			Weighted Average Grant Date Fair Value		Shares			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2021		559,368		$	40.03		323,081		$	48.56
Granted		500,222		$	29.81		255,327		$	33.57
Vested and settled		(152,735	)	$	41.03		—		$	—
Cancelled		(59,708	)	$	34.80		(62,176	)	$	55.70
Outstanding at December 31, 2022		847,147		$	34.18		516,232		$	40.29